The San Antonio STI TM CRC proposal represents an integrative, collaborative and innovative multi-disciplinary research effort to investigate and prevent important emerging causes of sexually transmitted diseases. It combines basic and clinical strategies with behavioral and epidemiological analyses and statistical/computing and administrative core support and focuses on underserved South Texas minority women (Mexican- and African-American) and their male partners. The women participants attend a dedicated clinic (designated Project SAFE), which is totally overseen by the San Antonio STI TM CRC and provides clinical evaluation and physical examination of study patients, collects and distributes genital tract and blood samples to specific projects and serves as the collection center for recruitment, interview and intervention activities. The targeted patient population is both understudied and disproportionately affected by STIs. The CRC's goals are to develop and test strategies and tools to understand the biology and infectious potential of specific STIs and prevent and control disease progression through vaccine, diagnostic, microbicide, behavioral and clinical characterizations and interventions. The San Antonio CRC is distinguished by very close collaborations among San Antonio STI TM CRC investigators and additional alliances with other CRC centers and industrial partners. Chlamydia trachomatis, Trichomonas vaginalis, and Mycoplasma genitalium are the emphasized STI agents although correlations with other STIs and urogenital infections are examined through project and core overlap and collaborations. A special strength of the San Antonio CRC is the long-term working relationships that exist among the key investigators, which have been ongoing for many years and are centered in the Departments of Microbiology and Immunology and Obstetrics and Gynecology of The University of Texas Health Science Center at San Antonio. As detailed in the STI TM CRC application the projects are 1: Novel Chlamydia Vaccine Candidates;2: Mucosal/Oral Antibody Diagnosis for Trichomonas vaginalis;3: Mycoplasma genitalium Persistence and Diagnosis;4: Dual STI Prevention Interventions for Minority Couples;and 5: Clinical Aspects of STDs in Dyads. These projects are supported by Statistical/Computing and Administrative Cores.